<?php

namespace fluiex\util;

/**
 * 文本处理工具类
 */
class Text
{

    public static function cutstr($string, $length, $dot = ' ...')
    {
        if (strlen($string) <= $length) {
            return $string;
        }

        $pre = chr(1);
        $end = chr(1);
        $string = str_replace(array('&amp;', '&quot;', '&lt;', '&gt;'), array($pre . '&' . $end, $pre . '"' . $end, $pre . '<' . $end, $pre . '>' . $end), $string);

        $strcut = '';
        if (strtolower(CHARSET) == 'utf-8') {

            $n = $tn = $noc = 0;
            while ($n < strlen($string)) {

                $t = ord($string[$n]);
                if ($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
                    $tn = 1;
                    $n++;
                    $noc++;
                } elseif (194 <= $t && $t <= 223) {
                    $tn = 2;
                    $n += 2;
                    $noc += 2;
                } elseif (224 <= $t && $t <= 239) {
                    $tn = 3;
                    $n += 3;
                    $noc += 2;
                } elseif (240 <= $t && $t <= 247) {
                    $tn = 4;
                    $n += 4;
                    $noc += 2;
                } elseif (248 <= $t && $t <= 251) {
                    $tn = 5;
                    $n += 5;
                    $noc += 2;
                } elseif ($t == 252 || $t == 253) {
                    $tn = 6;
                    $n += 6;
                    $noc += 2;
                } else {
                    $n++;
                }

                if ($noc >= $length) {
                    break;
                }
            }
            if ($noc > $length) {
                $n -= $tn;
            }

            $strcut = substr($string, 0, $n);
        } else {
            $_length = $length - 1;
            for ($i = 0; $i < $length; $i++) {
                if (ord($string[$i]) <= 127) {
                    $strcut .= $string[$i];
                } else if ($i < $_length) {
                    $strcut .= $string[$i] . $string[++$i];
                }
            }
        }

        $strcut = str_replace(array($pre . '&' . $end, $pre . '"' . $end, $pre . '<' . $end, $pre . '>' . $end), array('&amp;', '&quot;', '&lt;', '&gt;'), $strcut);

        $pos = strrpos($strcut, chr(1));
        if ($pos !== false) {
            $strcut = substr($strcut, 0, $pos);
        }
        return $strcut . $dot;
    }

}
